Electric switch



Patented Feb. 23, 1932 UNITED STATES PATENT ol-Flclz LOUIS A. M. PHYELAN, OF BELOIT, WISCONSIN, ASSIGNOR, BY MESNE vASSIGNMENTS,

T MINNEAPOLIS-HONEYWELL REGULATOR COMPANY, 0F MINNEAPOLIS, IIN- NESOTA, A CORPORATION OF DELAWARE ELECTRIC SWITCH Application med December 17, 1925. Serial No. 75,895.

My invention relates to electric switches and it has special reference to operating mechanisms therefor that serve to open and close associated electriccircuits in accordance with external thermal conditions which influence the operating mechanism.

One object of my invention is to provide an operating mechanism for a mercury contactor that is tilted by means of an operating element or actuator subjected to the infiuence of thermal conditions. p

One specific` application of my present invention relates to its use as a stack thermostatic switch and in such relation I shall describe it. As the operating element or actuator is disposed within the stack and under direct influence of the thermal conditions of the furnace or the like, there has existed marked dilliculty in keeping the operating element or actuator free from the products of combustion given off from the substance burned to create this thermal condition. Deposits of the productsof combustion on the operating element or actuator are detrimental to its operation; therefore a further object of the present invention is to minimize the extent of these deposits.

Tiltable mercury switches or contactors are used predominantly where a very small quantity of energy is available for actuating purposes because only a very slight tilting movement is necessary to effect a change of electrical circuit connection. Sinceit is impossible to insure the cessation of the actuating force at the same time that the limits of the switch or contactor movements have been reached, it is apparent that some provision must be made whereby the actuator may move through a greater range. This relative movement between the actuator and the contactor in my present invention is dependent upon a frictional engagement between them as will be hereinafter described.

Another' feature of the switch is its adaptability to be installed on the various types of stacks in present day use. The stacks usually have inclined surfaces on which the device is positioned and as it is usually desirable to` mount the`contactor and its casing in a substantially vertical plane, meansare provided to compensate for any angularity-between the planes of the switch and the stack wall. i

For a better understanding of the nature, scope and characteristics of my invention, reference may be had to the accompanying drawings in which- Figure 1 is a front view of an electrical switch mechanism embodying one form of my invention with the cover of the casing removed;

Fig. .2 isa sectional view taken on the line 2-2 of Fig. 1; and

Fig. 3 is an enlarged detail view showing the means for establishing frictional engagement between the actuator and the contacter.

Referring more particularly to the drawings, the switch comprises a casing having a cover 11 secured thereto by means of screws 12. An aperture is provided in the back wall of the caslng through which projects a bearing member 13 secured to-the casing and upon which bearing member is secured a tube 14 which projects a short distance into the stack 15. The tube 14 has an aperture 16 vwhich is disposed on the outside of the stack to afford a proper ventilation therethrough. Within the stack and in axial alignment with the tube is disposed a helical bimetallicl element 17 which is ixed or secured at one end to a projection 18 attached to the tube 14 by means of a screw 19. The outer extremity of the bimetallic element is adjustably secured to a rod 20 by means of a bracket 21 mounted on the rod 20 and a screw 22 attaching thev bimetallic element 17 to the bracket 21.A It is apparent, therefore, that when heat comes in contact with the bimetallic element, the nature of which is so well known that it is not believed necessary to elaborate upon, its expansion causes an axial rotation of the helical element to actuate accordingly the rod 20. Further, it is to be understood, that a cooling of the bimetallic element contracts it and changes its direction of movement in a similar manner and likewise the direction of axial rotation of the rod 20.

The rod 20 is rotatably mounted in the bearing 13 and extends therethrough into the casing 10. Mounted on the end of the rod ill and in frictional engagement therewith is a clip 23 for carrying the mercury-tube contaetor switch 24. Within the casing is mounted an insulating terminal block 25 upon which is positioned a plurality of binding posts 26 and to these latter may be connected the lead wires 27 which are connected to the electrodes sealed in the mercury tube contactor switch 24.

To form the frictional engagement between the rod of the actuating element and the mercury contactor, the rod is provided with a collar 28 rigidly secured thereto in any suitable manner. A collar-like member 29 is loosely secured on the shaft 20 by means of a nut 30, this member 29 functioning as a support for the contacter clip 23. The left hand end of the member 29 is formed with a socket 31. A spiral sprin 32 surrounds the shaft 20 and is conined y the collar 28 and another collar 33, the latter being free to slide longitudinally along the shaft 2() under the pressure of said spring 32 and push said member 29 against the nut 30, whereby said member 29 is gripped between collar 28 and nut 30 and is moved when the ,rod 20 is rotated. l

Positioned above the contaetor 24 and projecting into the wall of the casing are two sto or limiting members 34. `A pin 35 is rigldly secured to the collar 29 and has a relatively narrow range of travel between the stop members 34 thus limiting the distance through which said contactor may be tilted when actuated by the bimetallic element 17. The action apparent from the foregoing description is that the rotary movement of the rod 2O obtained from the actuating element 17, is imparted to the member 29 by reason of the spring 32 pressing the collar 33 against the end of the socketed portion of said member 29 which, in turn, is pressed against the nut 30. When the pin 35 contacts with one of the stop members 34, the movement of the member 29 is arrested. However, the actuating member 20 may continue to move, as it very frequently will, under the influence of the continued rotatable expansion or contraction of the bimetallic element, since the loose collar 33 will slide over the end of the socketed portion of the member 29 and permit the overriding movement of the actuator. However, immediately upon a reversed direction of rotation of the actuating element 17, the contactor supporting member 29 willl be picked up and moved in a reverse direction, it is not necessary to wait thereturn of the actuator to the point at which the contactor was previously arrested.

The purpose of the frictional mounting then, is to insure that upon a reversal of direction of the rotation of the helical bimetallic element 17 and the rod 20 an im. Y

mediate change vin direction of movement of the contacter 24 will take place notwithstand- Lemos? ing the distance the rod 2O has been allowed to rotate past the point at which the contaetor was arrested.

them. Also in spacing the convolutions a greater distance apart, the angles are greater and the further from a vertical plane these angles are, the less is the tendency toward a building up of the carbon deposits in a vertical relation. Therefore it is apparent that the carbon cannot accumulate between the convolutions and prevent the proper thermal iniuence upon the actuator as would be the case should the heat not pass therethrough. Further, such a condition would hinder the mechanical function of the actuator.

A further feature of this invention is the means whereby the switch may retain a vertical position regardless of the plane in which the wall of the stack is disposed. This is accomplished by means of a flange 36 bolted or otherwise secured to the stack wall 15, which former includes a projection 36 integral therewith and having an aperture 37 therethrough. The tube 14 and the actuating element 17 passes through the aperture 37 into the stack and is securely held in position by the bolts 38. The aperture 37 is of a frustreeonical shape with its smaller diameter substantially the same as that of the tube. With the smaller diameter of the aperture acting in the manner of a pivot and by means of adjusting the bolts 38, any degree of tilt may be obtained in order that the switch may be4 positioned in a vertical plane.

From the foregoing description it will be understood that my electric switch comprises a helical or coiled bimeta-llic actuator which is adapted to rotate through a relatively wide range, a contactor switch which is mounted upon a holder or clip that is rotated by this actuator, the holder being adapted to move through a relatively narrow and limited range, and frictional engaging means between the holder and the actuator whereby relative movement between the actuator and the holder may obtain when the rotatable movement of the actuator exceeds a predetermined range. Moreover, that whenever the aetuator reverses its direction of movement it immediately causes the holder and thereby the contacter to be tiltably moved in the opposite direction from which it was previously tilted.

While I have herein shown and described one embodiment of my invention, it is to be understood that I do not desire to be limited lib to this exact structure or the details thereof.

Various other forms will be apparent to one skilled in the art and consequently the invention is to be limited only by the scope of the appended claims and the prior art.

I claim:

1. In an electrical switch structure, a casing, a tiltable mercury contactor within said casing, a holder for said contactor, a tubular member rigidly secured te said casing and extending laterally therefrom, thermostatic actuating means exteriorl of said casing disosed adjacent the end o said tubular memer and in axial alignment therewith, said thermostatic actuating means comprising a helically coiled bimetallic element, one'end of said element being rigidly secured to said tubular member, and a rod centrally located with respect to said helical coil and said tubular member attached to the free end of said 'coiled element, yielding continuously acting slip frictional connecting means between said contactor holder and said rod to allow said free end of the coil to move without restraint throughout its. entire range, said frictional connection comprising a socketed rotarily mounted member upon which said contactor holder is mounted, and anotherI rotarily mounted member positioned on said rod and having a frictional connectionl therewith within the said socketed portion, said helical element being capable of being subjected to heating zones without afecting unduly said contact-or housed in the casing.

2. In an electrical switch structure, a casing, a tiltable mercury contactor within said casing, a holder for said contactor, means for limiting the extreme movements of said contactor, a tubular member rigidly secured to said casing and extending laterally there from, thermostatic actuating means exteriorly of said casing disposed adjacent the end of said tubular member and in axial alignment therewith, said thermostatic actuating means comprising a helically coiled bimetallic element, one end of said element being rigidly secured to said tube, and a rod centrally located with respect to said helical coil and said tubular member attached to the free end of said bimetallic element, yielding continuously acting vslip frietional connecting means between said contactor holder and said rod to allow said tree end of the coil to move without restraint throughout its entire range, said frictional connecting means comprising a socketed rotarily mounted member upon which said contactor holder is mounted, and another rotarily mounted member positioned on said rod and having a frictional connection therewith within the said socketed portion to permit an overriding movement in either direction, but immediate reversal of movement upon reversal of said actuating means, said helical element being capable of being subjected to heating zones without affecting unduly said contactor housed in the y casing.

3. In an electrical switch structure, a casing, a tiltable mercury contactor within said casing, a tube rigidly secured to said casin and extending laterally therefrom, a helica thermostatic actuating means exteriorl of said casing disposed adjacent to one si e of said tube and in axial alignment therewith for operating said contactor, and means for positioning said casing in a desired plane.

4. In an electrical s witchstructure, av casing, a tiltable mercury contactor within said casing, a tube rigidly secured to said casing said casing disposed adjacent to one side of said tube and in axial alignment therewith for operati-ng said contactor, and an apertured fiange through which said tubeextends, said aperture being of a frusto-conical shape to permit of an axial tilt of said tube, and securing means between said tube and said aperture.

6. In an electrical switch structure, a casing, a tiltable mercury contactor within said casing, a tube rigidly secured to said casing and extending laterally therefrom, a helical thermostatic actuating means exteriorly of said casing disposed adjacent to one side of said tube and in axial alignment therewith for operating said contactor, and an apertured iange through which said tube extends, said aperture being of a.frustoconical shape to permit of an axial tilt of said tube, and a pair of oppositely located bolts for securing said tube in any desired position.

7. In a device of the character descrilwd. a casing, switching means housed therein. spaced stop members for limiting to a relatively small range the extremes of movement of said switching means. coiled actuating means exteriorly of said casing for said switching means` and rotatable means mounted on said actuating means and carrying said switching means, said carrying means having an varm extending to engage said stop members to limit the degree of movement of said switchingmeans and comprising a yielding continuously acting frictional slip conneet-ion to permit Aot an overriding of said coiled means thus allowing the latter to move without restraint throughout its entire relatively large range but insuring immediate reverse movement of said switching means upon a reverse movement of said actuating means.

8. In a device of the character described, a casing, switching means housed therein, spaced stop members for limit-ing to a relatively small range the extremes of movement of said switching means, coiled actuating means exteriorly of said casing for said switching means, and means mounted on said actuating means for carrying said switching means, said carrying means having an arm extending to engage said' stop members to limit'the movement of said switching means and comprising a yielding continuously acting frictional slip connection to permit of an overriding of said coiled actuating means thus allowing the latter to move without restraint throughout its entire relatively large range but insuring immediate reverse movement of said switching means upon a reverse movement of said actuating means.

9. In a device of the character described, switching means, spaced stop members for limiting the extremes of movement of said switching means, actuating means for said switching means, said actuating means comprising a rotatable member and a coiled member connected thereto and acting in the same direction of rotation as said rotatable member, and means mounted on said actuating means for carrying said switching means, said means adapted to engage said stop members to limit to a relatively small range the movement of said switching means and to permit of an overriding of said actuating means relative to said switching means thus allowing said-coiled member to move without restraint throughout its entire relatively large range but insuring immediate reverse movement of said switching means upon a reverse movement ofl said actuating means.

10. In a device of the class described, a casing, a tiltable switch housed therein, stop members for limiting the span of movement of said switch to a relatively narrow range, a coiled thermostatic means eXteriorly of said casing for actuating said switch, a rotatably mounted member coaxial with said thermostatic meansand rotatable thereby throughout a relatively large range, an abutment mounted on said member, an arm for carrying said tiltable switch and extending to engage said stop members, and spring means for pressing said arm against said abutment for effecting a yielding continuously act-ing slip frictional engagement between said switch and said coiled th-ermostatic means thus allowing the latter ,to move without restraint throughout its relatively large range.

11. In a devie of the class described, a tiltable switch/spaced stop members for limiting to a relatively small range the movements in both directions of said switch, a

mimosa coiled thermostatic actuating means for said switch having a relatively large rangel of movement and comprising a rotatable mounting member coaxial with said thermostatic means, an arm on said mounting member for carrying said switch and extending to engage said stop members, and spring means for effecting a yielding continuously acting slip nfrictional engagement between said mounting member and said coiled actuating means whereby the latter may move without restraint throughout its entire range.

l2. An electric switch comprising a main support, a shaft journaled in said support, a coiled thermostatic element anchored on said support and secured to the shaft to rotate the latter through a relatively large range in either direction throughout the whole range of temperature responsive movement of said coiled thermostatic element, a contact carrying element carried by said shaft and relatively rotatable thereon, a friction clutch interposed between said shaft and said contactcarrying element to establish a yieldingcontinuously acting slip connection therebetween, and means to limit the angular movement of said contact-carrying element about the axis of said shaft independently of the degree of the angular movement of said shaft about its axis which allows said coiled element to move without restraint throughout its entire range of movement.

la. An electric switch comprising a main support, a shaft journaled therein, a coiled temperature responsive element having one end connected to said support and being also connected to said shaft to impart thereto an unlimited range of rotatable movement in either direction, a contact-carrying element operated by said shaft to open and close an electric circuit, a friction clutch incorporating a yielding continuously acting slip connection between said shaft and said contact carrying element, and means for limiting the movement in both directions of said contactcarrying element within a relatively narrow span ,while said shaft may move independently and without restraint upon said coiled element throughout its unlimited range and beyond the span of movement of said contact-carrying element.

14. An electric switch comprising a support, a shaft journaled in said support, a coiled heat responsive clement secured to said shaft to rotate the same in either direction and in unison therewith throughout the unlimited r'ange of temperature responsive movement of said heat responsive element, a contact-carrying element, means for limiting the movement thereof to a relatively narrow range with respect to the unlimited range of movement allowed to said shaft, and a friction clutch interposed between said contactcarrying element and said shaft thereby establishing a yielding continuously acting slip connection therebetween whereby they may move in unison within the narrow range of movement allowed to said contact-carrying. element but allowing relative movement therebetween when the contact-carrying element reaches the limit of its movement in either direction whereupon said coiled heat responsive, element and said shaft may move without restraint throu hout their unlimited lo range and whereby sai shaft and said contact-carrying element always move in unison whenever said shaft reverses its direction of movement. v 15. An electric switch comprising a support, a shaft journaled therein, a coiled thermostatic element coaxial with said shaft and havin one end secured to said sup rt and the ot er end connected to said sha t where-- by the latter rotates in unison with the former throughout the relatively large range -of temperature responsive movement of said coiled element, a switching means, and a yielding continuously acting rictional slip connection between said rod and said switching means for actuating the latter upon the rotation of the rod but permitting the rodA to continue without restraint its rotation after the switching means has reached its limit of operation thus imposing no strain upon said 3o coiled element throughout itsv temperature range. A

v 16. A thermostatically operated electric switch comprising a support; a switching means movable through a relatively narrow 85 range, a rod rotatabl mounted in said support, a. thermostatic e ement coiled about said rod and having one end connected thereto and its other end connected to said support whereby the rod will be rotated by the coiling` and uncoiling of said thermostatic element throughout the entire range of temperature responsive movement of said coiled thermostatic element, and a yielding continuously acting frictional slip connection between said rod and said switching means for actuating the latter upon the rotation of the rod but permitting the ro'd to continue its rotation without restraint uponv said coiled thermostatic element after the switching means has reached its limit of o eration.

' In witness whereo I have hereunto subscribed my name. LOUIS A. M. PHELAN. 

